This invention relates to coating materials that can be used on sulfur vulcanized rubber articles such as tires and hoses, and to sulfur vulcanized articles that have indicia or a protective coating applied thereon with this new coating material.
The marking of indicia or ornamental designs on prevulcanized rubber articles with a coating material, such as paint, has been felt to be desirable to a long time. For instance, U.S. Pat. Nos. 1,741,997 and 1,784,118, both issued in 1928, taught the use of colored rubber cements for making ornamental designs on tire sidewalls. U.S. Pat. No. 2,088,561, issued in 1937, taught a "liquid tire cover" that was essentially a paint applied to a preformed tire. However, as pointed out at column 1, lines 65 to 73 of U.S. Pat. No. 3,623,900, issued in 1971: "These suggestions have never lead to satisfactory tires, principally because the materials suggested as the rubber cement or rubber solution were inadequate to provide colored sidewall facings of the necessary adhesion to the rest of the vulcanized tire and durability. After a period of time, a tire sidewall facing applied according to the teaching of these prior suggestions cracked and delaminated from the tire".
Various other materials that have been proposed for use as coatings on vulcanized rubber articles include epoxy systems (U.S. Pat. No. 3,623,900 issued in 1971), fluorescent paint (U.S. Pat. No. 3,607,498 issued in 1971), polyurethane (U.S. Pat. Nos. 3,979,547 issued in 1976 and 4,136,219 issued in 1979), and slip coatings containing silicone gum (U.S. Pat. No. 3,202,540 issued in 1965).